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KVM: VMX: Frame in ENCLS handler for SGX virtualization

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Introduce sgx.c and sgx.h, along with the framework for handling ENCLS
VM-Exits.  Add a bool, enable_sgx, that will eventually be wired up to a
module param to control whether or not SGX virtualization is enabled at
runtime.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Message-Id: <1c782269608b2f5e1034be450f375a8432fb705d.1618196135.git.kai.huang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-04-12 16:21:38 +12:00 committed by Paolo Bonzini
parent 3c0c2ad1ae
commit 9798adbc04
4 changed files with 73 additions and 3 deletions
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2
arch/x86/kvm/Makefile
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@ -23,6 +23,8 @@ kvm-$(CONFIG_KVM_XEN) += xen.o
kvm-intel-y += vmx/vmx.o vmx/vmenter.o vmx/pmu_intel.o vmx/vmcs12.o \
vmx/evmcs.o vmx/nested.o vmx/posted_intr.o
kvm-intel-$(CONFIG_X86_SGX_KVM) += vmx/sgx.o
kvm-amd-y += svm/svm.o svm/vmenter.o svm/pmu.o svm/nested.o svm/avic.o svm/sev.o
obj-$(CONFIG_KVM) += kvm.o

50
arch/x86/kvm/vmx/sgx.c Normal file
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@ -0,0 +1,50 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2021 Intel Corporation. */
#include <asm/sgx.h>
#include "cpuid.h"
#include "kvm_cache_regs.h"
#include "sgx.h"
#include "vmx.h"
#include "x86.h"
bool __read_mostly enable_sgx;
static inline bool encls_leaf_enabled_in_guest(struct kvm_vcpu *vcpu, u32 leaf)
{
if (!enable_sgx || !guest_cpuid_has(vcpu, X86_FEATURE_SGX))
return false;
if (leaf >= ECREATE && leaf <= ETRACK)
return guest_cpuid_has(vcpu, X86_FEATURE_SGX1);
if (leaf >= EAUG && leaf <= EMODT)
return guest_cpuid_has(vcpu, X86_FEATURE_SGX2);
return false;
}
static inline bool sgx_enabled_in_guest_bios(struct kvm_vcpu *vcpu)
{
const u64 bits = FEAT_CTL_SGX_ENABLED | FEAT_CTL_LOCKED;
return (to_vmx(vcpu)->msr_ia32_feature_control & bits) == bits;
}
int handle_encls(struct kvm_vcpu *vcpu)
{
u32 leaf = (u32)kvm_rax_read(vcpu);
if (!encls_leaf_enabled_in_guest(vcpu, leaf)) {
kvm_queue_exception(vcpu, UD_VECTOR);
} else if (!sgx_enabled_in_guest_bios(vcpu)) {
kvm_inject_gp(vcpu, 0);
} else {
WARN(1, "KVM: unexpected exit on ENCLS[%u]", leaf);
vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
vcpu->run->hw.hardware_exit_reason = EXIT_REASON_ENCLS;
return 0;
}
return 1;
}

15
arch/x86/kvm/vmx/sgx.h Normal file
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@ -0,0 +1,15 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __KVM_X86_SGX_H
#define __KVM_X86_SGX_H
#include <linux/kvm_host.h>
#ifdef CONFIG_X86_SGX_KVM
extern bool __read_mostly enable_sgx;
int handle_encls(struct kvm_vcpu *vcpu);
#else
#define enable_sgx 0
#endif
#endif /* __KVM_X86_SGX_H */

9
arch/x86/kvm/vmx/vmx.c
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@ -57,6 +57,7 @@
#include "mmu.h"
#include "nested.h"
#include "pmu.h"
#include "sgx.h"
#include "trace.h"
#include "vmcs.h"
#include "vmcs12.h"
@ -5607,16 +5608,18 @@ static int handle_vmx_instruction(struct kvm_vcpu *vcpu)
return 1;
}
#ifndef CONFIG_X86_SGX_KVM
static int handle_encls(struct kvm_vcpu *vcpu)
{
/*
* SGX virtualization is not yet supported. There is no software
* enable bit for SGX, so we have to trap ENCLS and inject a #UD
* to prevent the guest from executing ENCLS.
* SGX virtualization is disabled. There is no software enable bit for
* SGX, so KVM intercepts all ENCLS leafs and injects a #UD to prevent
* the guest from executing ENCLS (when SGX is supported by hardware).
*/
kvm_queue_exception(vcpu, UD_VECTOR);
return 1;
}
#endif /* CONFIG_X86_SGX_KVM */
static int handle_bus_lock_vmexit(struct kvm_vcpu *vcpu)
{